Devices that produce a curtain of air such as air knives are used in a variety of different applications for cleaning and drying purposes. For example, an air knife can be used to blow dirt and other debris off objects such as parts, sheets or webs including conveyors. An air knife can also be used to help cool or dry such objects.
To optimize performance, the air curtain preferably forms a knife-edge as it hits the objects being cleaned or dried. This maximizes the force per unit area produced by the air curtain. The velocity of the discharging air and the thickness of the air curtain are two key factors involved in producing a good knife-edge.
Unfortunately, many existing air knives produce air curtains that have a great deal of turbulence. This turbulence reduces the velocity of the air curtain and also can cause the air to fan out as it exits the air knife leading to a relatively wider air curtain. The decreased velocity and increased width reduce the impact of the air curtain adversely affecting the performance and effectiveness of the air knife.